Cutting mechanisms for metallic can body trimmers and the like

ABSTRACT

A mandrel positioned can body is retained stationary with a wall to be trimmed projecting axially through an outer stationary cutter ring while an internal, circular trimmer knife is moved outwardly to penetrate the can wll acting against the cutter ring and the knife axis is then moved in a circular path around the can wall and cutter ring to trim the can wall followed by trimmer knife inward retraction. The trimmer knife is also preferably rotatable about its own axis and interfaces during the trimming operation against the cutter ring by axial abutting respective radial surfaces. The trimmer knife inward and outward movement relative to the cutter ring is controlled by a cam ring having an inwardly facing cam surface and adjustment means is preferably associated with the cam ring for radial trimmer knife movement control and can wall penetration. The cutter ring and trimmer knife are each mounted so that they may be disassembled, surface ground for sharpening and reassembled with the reassembly assuring exact cutting surface relaignment automatically.

Unite States Patent [191 Paramonoff [451 Oct. 8, 1974 [75] Inventor: Elpidifor Paramonoff, Los Angeles,

Calif.- [73] Assignee: Standu'n lnc., Compton, Calif. [22] Filed: Jan. 12, 1973 [21] Appl. No.: 323,198

[51] lint. Cl B23b 5/14 [58] Field of Search 82/59, 82, 101 R, 46, 70.1, 82/53, 57, 58, 54, 61; 83/54, 178

3,359,841 12/1967 Cvacho et a1 83/54 X 3,400,620 9/1968 Armbruster-et al. 82/47 3,646,840 3/1972 Bozek 82/82 3,756,103 9/1973 Cvacho et a1. 82/101 R Primary Examiner.Francis S. Husar Assistant Examiner-W. R. Briggs Attorney, Agena or Firm-Mahony, Schick & Cislo [57] ABSTRACT A mandrel positioned can body is retained stationary with a wall to be trimmed projecting axially through an outer stationary cutter ring while an internal, circular trimmer knife is moved outwardly to penetrate the can wll acting against the cutter ring and the knife axis .is then moved in a circular path around the can wall and cutter ring to trim the can wall followed by trim mer knife inward retraction. The trimmer knife is also preferably rotatable about its own axis and interfaces during the trimming operation against the cutter ring by axial abutting respective radial surfaces. The trimmer knife inward and outward movement relative to the cutter ring is controlled by a cam ring having an inwardly facing cam surface and adjustment means is preferably associated with the cam ring for radial trir'nmer knife movement control and can wall penetration. The cutter ring and trimmer knife are each mounted so that they may be disassembled, surface ground for sharpening and reassembled with the reassembly assuring exact cutting surface relaignment automatically.

15 Claims, 27 Drawing Figures PATENTEB 8 IBM sum 01 or 11 Fig. 2.

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PAIENTEUHBI 8M4 SHEET 05 U? H PAIENI nnm sum sum 01 or 11 PATENIEU 1 74 saw can? u PATENTEB 81974 sum 10 or 1 CUTTING MECHANISMS FOR METALLIC CAN BODY TRIMMERS AND THE LIKE BACKGROUND OF THE INVENTION This invention relates to'cutting mechanisms for metallic can body trimmers and the like, and more particularly, to such cutting mechanisms making use of a unique system of metal cutting or trimming components positioned and actuated such that a vastly improved metallic can body trimming operation is accom plished. Furthermore, according to certain of the principles of the present invention, the cutting mechanisms also preferably make use of a unique relationship between the metal cutting or trimming tool surfaces so as to provide a clean and accurate severance of the metal at the exact location desired. Still further, the cutting mechanisms of the present invention preferably incorporate a new and different form of mounting of the respective metal cutting or trimming tools such that removal and sharpening of these tools is quickly and easily accomplished with the remounting thereof being equally convenient and, at the same time, automatically assures exact accurate tool repositioning despite the tools being slightly altered from the sharpening thereof, thereby eliminating the necessity for time consuming realignments.

In the production of seamless metallic can bodies of the type having integral bottom walls and open top ends ultimately usuable for containing beverages, the can bodies are usually formed from aluminum, tinplate or black iron by drawing and wall ironing operations. The can bodies arrive at the can body trimmers in finished form with the exception of the final wall trimming to be accomplished by the trimmers. In final form, the can bodies must be of a determined axial length and the open ends thereof must be smoothly trimmed for finally receiving the second end walls secured thereon during the beverage filling operations.

In the can body final form, the walls thereof are in the order of 0.008 inch thickness and other than relatively exact final size limitations for the can body, one of the prime requirements in the can body wall trimming op eration is that the trimming must be performed from internally thereof out so that any slight burr on the open end thereof after the trimming operation will be at the outer surface rather than the inner surface. This is a basic requirement of the industry for various reasons, including the necessity of preventing accidental deposit of severed metal slivers into the internal portion of the can body, particularly during the final filling and second end wall application. Also, various difficulties can be caused by an internal burr during the final second end wall application and sealing.

Thus, in all of the prior modern metallic can body trimmers, various mechanisms have been incorporated therein providing certain interactions between metal cutting tools thereof and the metallic can body walls being trimmed. Prior to the unique mechanisms and metal cutting tool inter-relations of the present invention, however, none of the metallic can body trimmers have been completely satisfactory. Three major factors are involved, namely, the metallic can body walls must be trimmed to relatively precise dimensions on a continued repeating basis over long production runs, the metal cutting or trimming operations must be such so as to produce cleanly trimmed can body open ends with a minimal outer edge burr resulting in the elimination of the possibility of resulting metal slivers, and the metal cutting or trimming tools must be mounted for convenient removal, resharpening and remounting in a minimum amount of time for the maximum efficient use of trimmer production time.

With at least certain forms of the prior metallic can body trimmers, the one-piece metallic can body is positioned axially over a mandrel and telescoping a cylindrical internal trimming knife positioned axially underlying the ultimate scrap ring portion of the can walls to be trimmed therefrom. The internal trimming knife has outer circumferential dimensions as close as possible to the internal dimensions of the can body walls while still allowing the can body walls to be telescoped thereover on a reasonable production cycling basis. During the actual trimming operation and the severing of the scrap ring from the can body, the can body and cylindrical internal trimming knife are simultaneously rotated and an outer trimming knife is moved inwardly against and at least partially penetrating the can walls and then rotated about the can walls to sever the scrap ring from the can body while this scrap ring is supported by the inner or internal trimming knife.

In other words, while the portion of the can body walls ultimately forming the scrap ring is internally supported by the internal trimming knife, the outer or external trimming knife is moved inwardly axially adjacent a side of the internal trimming knife axially facing the closed end of the can body being trimmed. The outer trimming knife moves inwardly to penetrate the can body walls with facing radial surfaces of the respective inner or internal and outer trimming knives coacting to completely sever the scrap ring from the can body walls. More important, since the portion of the can body walls ultimately forming the scrap ring is internally supported, the can walls axially adjacent the can body trimmed edge to be produced are unsup ported and forced inwardly by the outer trimming knife in order that the trimming operation may be accomplished and so that any remaining burr on such trimmed edge will be an outer, rather than an inner, projecting burr.

With all of the components involved, namely, the can body, the inner or internal trimming knife and the outer or external trimming knife all necessarily rotatable, and even though the can body and internal trimming knife are simultaneously rotatable, considerable difficulties have been presented in providing such rotatable mounting. Keeping in mind that the can bodies must be trimmed to relatively precise dimensions and the resulting trimmed edge must be of a clean nature as hereinbefore discussed, with this dual rotation, it is extremely difficult to maintain precise dimensions for the trimming tools or knives over an extended period of production time. Exact alignments between the cutting tools or knives, as well as with the can body mounting and retainment, must be maintained if these requirements are to be satisfied.

As a further matter, with these prior forms of trimmers, the portion of the particular can body being trimmed which remains and is to be used is deformed inwardly during the trimming operation while the can wall portion ultimately forming the scrap ring and finally disposed of is supported by the inner or internal trimming knife. This is necessary with these prior trimmers in order to produce the outer, rather than inner,

burr on the can wall cut edge so that in this prior trimming component arrangement it is unavoidable. Even though unavoidable, however, it does present an objectionable metal cutting arrangement resulting in the same difficulties in attempting to obtain precisely trimmed dimensions for the can body in a cleanly trimmed can body wall open end.

Obviously, since the inner and outer trimming knives of these prior trimmers are metal cutting tools, the cutting surfaces thereof must be maintained in a sharpened condition at all times. This requires frequent dismounting and removal, sharpening, and remounting during which the production time of the particular trimmer is interrupted. With the complex rotational motions and other motions involved, it has been quite a time-consuming task to perform these tool sharpening operations resulting in a considerable loss of trimmer production time, keeping in mind that every time a cutting tool or tools are dismounted, they must be remounted and very closely aligned with the other components.

The foregoing situation is even further aggravated by the fact that the outer or external trimming knife must be cam controlled for its movement inwardly, around the can body walls and then outwardly for every trimming cycle. With the prior machines, this cammed movement has been accomplished by the use of usual camming systems which necessarily are connected to the outer trimming knife and are positioned externally of the inner trimming knife support and mounting. This not only aggravates the alignment problems, but adds greatly to the outer dimensions of the overall trimmer due to the prior camming systems being relatively massive and cumbersome.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide cutting mechanisms for metallic can body trimmers and the like with which a vastly improved metallic can body wall trimming operation is accomplished resulting in a can body wall trim of maximum accuracy and of cleanly cut nature virtually eliminating any problems of improper metal cutting, and all on a high-speed, mass production related basis. According to certain of the principles of the present invention, the metallic can body and the walls thereof to be trimmed and a surrounding cutter ring are both retained stationary during the trimming operation so that the only movable component is the internal trimmer knife. This not only eliminates many of the problems of maintaining alignments between the various components for an accurate and clean can body wall trimming operation, but also reduces complexity of mounting mechanisms and reduces complexity of cutting tool servicing operations.

It is a further object of this invention to provide cutting mechanisms for metallic can body trimmers and the like wherein, according to certain of the principles thereof, a new and unique interaction between the cutting or trimming tools is used resulting in a more precise and accurately trimmed can body wall edge, while still meeting the requirements of the industry of locating any trimming resulting burr externally rather than internally abut the finally trimmed can body walls. In the preferred form, an outer cutter ring, preferably retained stationary, outwardly surrounds the can body walls and has a radially extending annular cutting surface thereon extending outwardly from the can body walls and facing axially the scrap ring ultimately to be produced by the trimming operation. The inner or internal trimmer knife is mounted inwardly retractable to permit axial telescoping of the can body walls thereover and through the outer cutter ring with the inner trimmer knife being movable outwardly to penetrate the can walls, then circumferentially around the can walls severing the scrap ring therefrom through interaction with the outer cutter ring and then back inwardly to retracted position during removal of the trimmed can body. With this arrangement, the can body walls are supported outwardly by the outer cutter ring during the trimming operation being forced thereagainst by the outward movement of the inner trimmer knife and the ultimate scrap ring portion of the can walls is the only portion thereof severely deformed during the trimming operation so as to produce a more precise and accurate metal trim of the can body while still maintaining any possible burr externally as required.

It is also an object of this invention to provide cutting mechanisms for metallic can body trimmers and the like wherein either or both of the important cutting or trimming tools may be specifically and particularly mounted for removal, sharpening and remounting in a manner automatically assuring proper and accurate realignment therebetween despite the slight changes in size thereof from the sharpening operation. With the interaction between the internal trimmer knife and outer surrounding cutter ring being preferably an axial reaction between respective radially extending cutting surfaces, the required sharpening operations of the tools may be merely one of surface grinding and the realignments between the respective tool cutting surfaces is one of axial realignment, that is, each in its respective proper radial plane for the proper axial interaction therebetween during the trimming operation. The respective trimming knife and cutter ring tools are, therefore, through unique mounting means, mounted so that the respective radially extending cutting surfaces thereof are always replaced in the exact same radial planes despite the obvious slight change in tool axial thicknesses, thereby automatically producing proper realignment in a fast and efficient manner.

It is still another object of this invention to provide cutting mechanisms for metallic can body trimmers and the like wherein, according to certain other principles of the present invention, the internal trimmer knife in its relatively complex movements is cam controlled by an internal cam surface which may be supplied by a cam ring merely positioned axially spaced of the trimmer knife and its mounting mechanisms, thereby reducing the overall size of the trimmer and eliminating the problems of the prior cam mechanisms, not only of size, but of the mechanical connections thereof to the trimmer knife. Furthermore, in the preferred form of this internal cam surface on the trimmer knife controlling can ring, the can ring may be mounted simultaneously rotatable with the frame directly mounting the trimmer knife but at a different rotatable speed. In this manner, the trimmer knife controlling cam ring may be reduced to a minimum in size while still providing complete and accurate control for the trimmer knife in its relatively complex movements.

It is still an additional object of this invention to provide cutting mechanisms for metallic can body trimmers and the like wherein, despite the required relatively complex movements of the trimmer knife, the trimmer knife may be mounted conveniently adjustable for its radially outward and inward movement such that can body wall penetration by the trimmer knife can be quickly and conveniently adjusted to that required for accomplishing the desired can wall cutting or trimming. In the preferred form, with the trimmer knife and cutter ring interaction being supplied by their respective axially acting and radially extending cutting surfaces, the adjustment between these radially extending surfaces for increased or decreased can body wall penetration is merely one of adjusting radial overlap between the respective cutting surfaces. Thus, the adjustments between the respective radially extending cutting surfaces for can body wall penetration are relatively simple and of greatly reduced criticality as long as sufficient can body wall penetration is maintained.

Other objects and advantages of the invention will be apparent from the following specification and the accompanying drawing which are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of a metallic can body trimmer incorporating a preferred embodiment of the principles of the present invention;

FIG. 2 is a top plan view looking in the direction of the arrows 2--2 in FIG. ll;

FIG. 3 is a fragmentary, vertical sectional view looking in the direction of the arrows 3-3 in FIG. 2;

FIG. 4 is an enlarged fragmentary, horizontal sectional view looking in the direction of the arrows 4-4 in FIG. I and showing a pusher mechanism incorporated in the trimmer of FIG. I, the pusher mechanism being in fully withdrawn or retracted position;

FIG. 5 is an enlarged, fragmentary, vertical sectional view looking in the direction of the arrows 5-5 in FIG. 4 and showing the pusher mechanism still in fully retracted position;

FIG. 6 is an enlarged, fragmentary, vertical sectional view looking in the direction of the arrows 6-6 in FIG. 4 and showing the pusher mechanism still in the fully retracted position, but a can body positioned for contact thereby;

FIG. 7 is a fragmentary, vertical sectional view taken from the right hand portion of FIG. 6, but showing the pusher mechanism in fully retracted position immediately after the ejection of a trimmed can body therefrom;

FIG. 8 is an enlarged, fragmentary, vertical sectional view looking in the direction of the arrows 88 in FIG. 2 and showing a can body positioned over the trimming mandrel by the pusher mechanism as during a trimming operation;

FIG. 9 is an enlarged, vertical sectional view looking in the direction of the arrows 9-9 in FIG. 8;

FIG. 10 is a fragmentary, horizontal sectional view looking in the direction of the arrows l0-l0 in FIG.

FIG. III is a vertical sectional view looking in the direction of the arrows 11-11 in FIG. 10;

FIG. 12 is a fragmentary, vertical sectional view looking in the direction of the arrows l2--12 in FIG. 10;

FIG. 13 is an enlarged, vertical sectional view looking in the direction of the arrows 13-13 in FIG. 8;

FIG. 14 is a fragmentary, vertical sectional view looking in the direction of the arrows l4-l4 in FIG. 13;

FIG. 15 is a fragmentary, vertical sectional view looking in the direction of the arrows l5ll5 in FIG. 14;

FIGS. 16, 17, I8, 23 and 27 are diagrammatic views showing the pusher mechanism in various progressive stages of movement from fully retracted position through the movement thereby of an untrimmed can DESCRIPTION OF THE BEST EMBODIMENT CONTEMPLATED Referring to the drawings an embodiment of an overall metallic can body trimmer assembly is shown in FIGS. 1, 2 and 3, and includes an overall usual main frame generally indicated at 30 supporting and housing, in some cases, various working component assemblies necessary for an operable overall trimmer assembly. For purposes of convenience of description, the trimmer assembly will be described generally immediately below and the description will then be segregated into the individual working component assemblies for a specific description of each of these assemblies, finally followed by a general description of overall trimmer operation. The individual component assemblies or sub-assemblies to be specifically described are a feed and positioning mechanism assembly generally indicated at 32, a trimming mechanism assembly generally indicated at 34 and a scrap disposal assembly generally indicated at 36.

Returning to the overall trimmer assembly generally, electrical power is fed to the trimmer assembly through an electrical control panel 38 and into the main frame 30 through an enclosing electrical conduit 4%. A compressed air supply is similarly fed :into the main frame 30 and presented for those components requiring the same in the usual manner and as will be hereinafter specifically described particularly relative to the feed and positioning mechanism assembly 32. The main frame 30 also houses the principal electrical motor and connecting gearing systems necessary for the driving of the various component assemblies of the trimmer assembly, the operable connections therebetween being in the usual manner and as will be more clearly understood from the following specific descriptions.

The various parts and components of the trimmer assembly are formed of the usual materials and In the usual manner, all well known to those skilled in the art, except as specifically hereinafter pointed out. Furthermore, although a specific preferred embodiment of the various mechanisms is shown in the: drawings and hereinafter described, it is not intended to limit the principles of the present invention to the specific embodiment. Rather the principles of the present invention should be broadly construed within the limitations defined by the following claims.

FEED AND POSITIONING MECHANISM ASSEMBLY Referring particularly to FIGS. 1 through 8 of the drawings, the feed and positioning mechanism assembly 32 includes a generally vertical infeed guide 42 for feeding a continuous series of drawn and wall ironed untrimmed metallic can bodies 44 having closed ends 46 and open ends 48 downwardly for one at a time reception in pockets 50 of a rotatable star wheel 52. The untrimmed can bodies 44 are, at this stage and from the formation standpoint, substantially finished except for the final wall trimming operation which trims the can bodies to desired length. Furthermore, the untrimmed can bodies 44 are preferably formed of appropriate metals such as aluminum, tinplate and black iron, and have wall thicknesses in the order of 0.008ths inches thick, being useable for containing beverages, for instance, such as beer and soft drinks.

The star wheel 52 is of usual timed indexing form appropriately driven by means well known to those skilled in the art and timed for proper operation in relationship to the operation of the various other components as will be hereinafter described. As shown, the star wheel 52 rotates about a horizontal axis and moves the untrimmed can bodies 44 in timed indexing movement, counterclockwise as shown in FIG. 3 in two indexing steps to a feed station generally indicated at 54 where each particular can body is sensed by a proximity sensor 56 of usual form and in the usual manner to be sure that a can body is at the feed station for permitting operation of the other components of the assembly. As

will be apparent from a later description, the particular untrimmed can body 44 at the feed station 54 is removed therefrom for trimming and then is returned as a wall trimmed can body 58 with the progressive indexing movements of the star wheel 52 in two such indexing movements releasing the trimmed can bodies 58 into the downwardly angled outfeed guide 60, where the trimmed can bodies move downwardly by gravity into an appropriate receptacle or other conveying equipment (not shown).

At the feed station 54, the untrimmed can bodies 44 are retained by the star wheel 52 with the cylindrical axis thereof horizontal, the closed ends 46 to the left and the open ends 48 to the right as shown. Preferably axially aligned with the feed station 54 is a pusher mechanism generally indicated at 62 and shown in detail in FIGS. 4 through 6. The pusher mechanism 62 in retracted position is fully to the left of the feed station 54 (FIGS. 2, 5 and 6) but is movable axially to an extended position through the feed station 54 and the appropriate pocket 50 of the star wheel 52 and ultimately to a trimming station generally indicated at 64, the trimming station, as well as a trimming mandrel 66 at said station, being a part of the trimming mechanism assembly 34 to be hereinafter described.

As shown in FIGS. 4 through 6, the pusher mechanism 62 includes an axially extending, stationary vacuum tube 68 rigidly secured in communication with a vacuum supply tube 70 at its left hand end. A vacuum flow sensor 72 is connected in communication with the interior of the vacuum supply tube 70 (FIG. 5) for sensing the continued flow therein in the usual manner and is electrically connected to appropriate controls for interrupting or shutting down operation of the trimmer in the event of sensing a continuous flow of vacuum as will be hereinafter more completely described. The vacuum tube 68 terminates at its right hand end spaced axially from the feed station 54 in an ejector stop 74, although the opening of the vacuum tube communicates centrally therethrough opening to the right of the ejector stop (FIG. 6).

A pusher tube 76 telescopes the vacuum tube 68, being axially reciprocal thereon through appropriate bearings. At the left hand end, the pusher tube 76 terminates in a radially outwardly enlarged cylinder abutment collar 78, and at the right hand end, the pusher tube terminates spaced axially beyond the right hand end of the vacuum tube 68 in a radially enlarged vacuum cup 80, open to the right. A vertically upwardly extending guide 82 is secured to the cylinder abutment collar 78 and is, in turn, upwardly received into a guide block 84 slideably guided axially in a guide slot 86 for aiding and guiding the axial reciprocal movements of the pusher tube 76.

An ejector 88 is axially slideably mounted within the vacuum cup and the right hand end of the pusher tube 76, and includes a vacuum opening 90 therein opening axially to the right within the opening of the vacuum cup 80 and opening radially spaced from the ejector left hand end into the pusher tube 76. Thus, when the ejector 88 is moved to the left, as shown in FIG. 6, fully within the vacuum cup 80, the vacuum opening 90 thereof is exposed to the vacuum tube 68 and vacuum is supplied therethrough to the vacuum cup 80. When, however, the ejector 88 is moved fully forwardly or to the right projecting from the vacuum cup 80 as shown in FIG. 7, the vacuum opening 90 is closed off by the vacuum cup so that there is no vacuum flow therethrough and the vacuum tube 68 is closed off, all in a manner and for a purpose to be hereinafter described.

Directly forwardly or to the right of the cylinder abutment collar 78, the pusher tube 76 is telescoped by a fluid cylinder 92, preferably a penumatic cylinder, which is spaced outwardly from the pusher tube and is appropriately sealed at opposite ends thereof on the pusher tube for axial slideable movement relative thereto. Such slideable sealing of the cylinder 92 at the forward or right hand end thereof, is constituted by a piston 94 secured to the pusher tube 76. At the rearward or left hand end of the cylinder 92, the interior thereof is connected in communication with a fluid supply line 96 for supplying fluid, preferably gaseous fluid such as air, under pressure to the cylinder. Also communicating into the cylinder 92 preferably at the fluid or air supply line 96 is a pressure sensor 97 and a dump valve 99, the pressure sensor 97 being for sensing fluid or air pressure within the cylinder above a predetermined pressure and having electrical connection to the main controls of the trimmer for interrupting operation of the same upon such higher predetermined pressure being sensed, and the dump valve 99 being for exhausting air pressure from the cylinder at least above said predetermined pressure, these again being for a purpose to be hereinafter described.

As best seen in FIG. 4, the rearward end of the fluid or pneumatic cylinder 92 is pivotally connected at opposite sides thereof to toggle driving arms 98 arranged such that from the position shown in FIG. 4, forward pivoting of the driving arms 98 urges the cylinder 92 forwardly or to the right and opposite pivoting of the driving arms urges the cylinder rearwardly or to the left. The pivotal stroke of the driving arms 98 is arranged so that with fluid, preferably air or some other gaseous fluid, in the cylinder 92 under pressure, preferably in the order of 40 pounds per square inch, forward pivoting of the driving arms 98 will move the cylinder axially forwardly and through the piston 94 and contained air pressure within the cylinder, will move the pusher tube 76 axially forwardly from its fully retracted position at the left of the star wheel 52 forwardly to the right through the star wheel and to the trimming station 64, with opposite movement of the driving arms 98 retracting the pusher tube or rod rearwardly to the left back to fully retracted position by abutting engagement of the cylinder with the cylinder abutment collar 78 on the pusher tube or rod. The reciprocal movement of the pusher tube 76 is, therefore totally through the fluid or air cushion or pressure within the cylinder 92 and if the pusher tube should meet an obstacle producing an obstructing force sufficient to exceed the pressure within the cylinder, the cylinder can collapse by compressing the air therein, that is, the cylinder being positively driven can continue forward movement to the right while the pusher tube becomes stationary causing the piston thereof to compress the air within the cylinder. Furthermore, by sensing the pressure of the air within the cylinder 92 through the pressure sensor 97 at the air supply line 96, when the pressure within the cylinder reaches a predetermined higher pressure indicating the obstructing force of sufficient magnitude, the entire trimmer can be automatically shut down, while at the same time, the dump valve 99 will exhaust air pressure above the predetermined higher pressure at least for cylinder pressure to stay below the predetermined higher pressure or lower.

The pusher tube or rod 76 is, therefore, guarded through this collapsing axial pressure reacting cylinder arrangement of the cylinder 92 against severe damage in the event an intervening obstructing force of sufficient magnitude is met during pusher rod forward movement at the feed station 54, between the feed station and the trimming station 66 or at the trimming station until the pusher rod is fully extended. Such an obstructing force of sufficient magnitude could be caused by improper positioning of an untrimmed can body 46 at the feed station 541 or a damaged or deformed can body being so positioned, some obstruction accidentally entering the space between the feed and trimming stations 56 and 64, some obstruction on the trimming mandrel 66 of the trimming station 64 preventing an untrimmed can body 44 being smoothly telescoped over such trimming mandrel by the pusher rod 76, or an untrimmed can body Ml being improperly positioned carried by the pusher rod 76 so that it is not positioned to be smoothly telescoped over the trimming mandrel 66 at the trimming station 66. Any of these or other obstructions could cause a sufficient obstructing force to cause collapse of the cylinder 92 and this would automatically terminate operation of the trimmer preventing serious damage to the pusher tube or rod 76 or various other components at the trimming station 66 to be hereinafter described, as well as automatically cause exhausting or dumping of excess higher air pressure preventing serious damage to the cylinder Also, it will be noted that the positioning relationship between the vacuum tube 68 and the pusher tube 76 is such that when the pusher tube is fully retracted or fully to the left as shown in FIG. 7, the ejector 88 contacts the ejector stop 76 on the vacuum tube 66 and is forced forwardly or to the right relative to the vacuum cup projecting therefrom as shown. When, however, the pusher tube 76 is in any extended position relative to the vacuum tube 66, that is, sufficient that the vacuum cup 86 carries the ejector 66 away from contact with the ejector stop 76 ot' the vacuum tube 68, the ejector is free to move rearwardly or to the left relative to the vacuum cup and a slight resistance or rearward movement will cause such rearward movement of the ejector. This will place the ejector 66 in its rearward position relative to the vacuum cup 66 as shown in FIG. 6.

In operation of this feed and positioning mechanism assembly 32 or this portion of the trimmer, starting with the pusher tube 76 in fully retracted position as shown in FIG. 6, the star wheel 52 indexes positioning an untrimmed can body 44 at the feed station 54 ready for movement to the trimming station 64 for the trimming operation on the open end 48 thereof. At this time, the vacuum cup 66 is spaced from the untrimmed can body 64 and the ejector 66 is abutting the ejector stop 73 on the end of the vacuum tube 66 closing the ejector vacuum opening 96 and projecting axially forwardly or to the right from the vacuum cup. This, of course, is the ejecting position of the ejector 88 in which the ejector was automatically placed upon the pusher tube 76 returning to its fully retracted position at the termination of the immediately preceding cycle.

At this stage, therefore, with the pusher tube 76 in fully retracted position ready for the start of a complete cycle, the vacuum supply to the vacuum cup 86 is shut off or closed by the ejector 66 through the automatic positioning thereof and this vacuum control is immediately adjacent the vacuum cup. Furthermore, both the vacuum cup 86 and its internal ejector 66 are slightly spaced axially rearwardly from, but exactly axial aligned with the untrimmed can body 66 that has been moved into the feed station 56. Air pressure of approximately 66 psi is contained within the cylinder 92 so that an air cushion of determined pressure is maintaining the proper positioning between the cylinder and the pusher tube 76 with the rearward end of the cylinder axially abutting the cylinder abutment collar 76 on the pusher tube.

Starting a cycle, the driving arms 98 begin forward pivotal movement to the right as shown in FIG. 4}, moving the cylinder 92 axially forward carrying the pusher tube 76 axially forward. The axially projecting ejector 88 first contacts the closed end 66 of the untrimmed can body 44 and since the rearward end of the ejector has moved axially away from the ejector stop 74!- of the vacuum tube 68, the resistance of the untrimmed can body moves the ejector axially rearwardly telescoping the same fully within the vacuum. cup 86. Virtually simultaneously, the vacuum cup 86 contacts the closed end 46 of the untrimmed can body 64 and with the ejector 68 spaced axially rearwardly relative to the vacuum cup 86, a vacuum supply is received from the vacuum tube 68 through the now open ejector vacuum openings 96 and into the vacuum cup 66, thereby vac uum gripping the untrimmed can body 66. This effective vacuum action takes place virtually instantaneously with the rearward telescoping of the ejector 88 and the opening of the vacuum openings 96 since no lengthy vacuum lines are required to be exhausted in view of the vacuum control being immediately adjacent the vacuum cup 80.

Continued forward or feed stroke movement of the pusher tube '76 forces the untrimmed can body 44 with its open end 48 first from its nesting in the star wheel 52 at the feed station 54 axially to the trimming station 64 and ultimately over the trimming mandrel 66 to the position shown in FIG. 8. In this pushing movement of the pusher tube 76, complete control of the untrimmed can body 44 is maintained by the described vacuum gripping thereof and as the untrimmed can body is forced to completely telescope the trimming mandrel 66, the final fully extended positioning of the cylinder 92 by the driving arms 98 is slightly beyond that necessary for the pusher tube 76 to fully telescope this untrimmed can body 44 over the trimming mandrel 66. This, therefore, moves the cylinder 92 slightly axially forwardly relative to the pusher tube 76 to the positioning of the pusher tube piston 94 shown by the phantom line 100 and the positioning of the cylinder abutment collar 78 of the pusher tube shown at phantom line 102 in FIG. thereby slightly compressing the air within the cylinder and maintaining axial pressure against the untrimmed can body 44 to maintain telescoped positioning thereof on the trimming mandrel 66. Although this increase in pressure within the cylinder 92 will be sensed by the cylinder pressure sensor 97, it is not a sufficient increase to cause the cylinder pressure sensor to interrupt or shut down operation of the trimmer or the dump valve 99 to exhaust excess air pressure.

After the can body trimming operation, to be hereinafter described, the driving arms 98 begin to pivot rearwardly carrying the cylinder 92 rearwardly abutting the cylinder abutment collar 78 of the pusher tube 76 to likewise begin movement of the pusher tube rearwardly, this being the start of the return or retraction stroke. Due to the vacuum gripping of the vacuum cup 80, the now trimmed can body 58 is withdrawn from the trimming mandrel 66 and the trimming station 64. The pusher tube 76 thereby moves the trimmed can body 58 from the trimming station 64 back to the feed station 54 renested within the star wheel 52, the pusher tube approaching the end of its retraction stroke and its fully retracted position.

As shown in FIG. 7, as the pusher tube 76 is finally moved into its fully retracted position in this retraction stroke, the ejector 88 contacts the vacuum tube ejector stop 74 which moves the ejector forwardly relative to the vacuum cup 80 causing the ejector to contact the closed end 46 of the trimmed can body 58. As the pusher tube 76 finally moves in to its fully retracted position, the ejector 88 forces the trimmed can body 58 axially from vacuum gripping by the vacuum cup 80 while simultaneously closing off the vacuum supply to the vacuum cup from the vacuum tube 68 through the relative ejector forward movement. The trimmed can body 58 therefore, is now free of control by the pusher tube 76 and the star wheel 52 may be indexed to bring the next untrimmed can body into the feed station 54 ready for the cycling of the mechanism.

As hereinbefore alluded to, if the untrimmed can body 44 and pusher tube 76 during the forward or feed stroke should meet one of the various possible obstructing forces hereinbefore described, the pusher tube forward movement may be stopped with the forward movement of the cylinder 92 continuing. If this obstructing force is sufficient to overcome the 40 psi pressure within the cylinder 92, the cylinder will begin to collapse, that is, relative axial movement between the pusher tube and the cylinder, thereby increasing the cylinder internal air pressure. Once this cylinder internal air pressure reaches a predetermined amount, say by relative movement between the pusher tube 76 and cylinder 92 to the phantom line positioning of the pusher tube piston 94 as shown at 103 in FIG. 6, the cylinder pressure sensor 97 senses this increased pressure to the predetermined pressure and automatically, through usual electrical connections, shuts down the trimming equipment while the dump valve 99 exhausts the excess air pressure. This, thereby, guards the trimming equipment against extensive damage.

Furthennore, if the pusher tube vacuum cup ever wrongly contacts an untrimmed can body 44, or the can body closed end 46 is split or broken from improper forming, or for this or some other reason loses its vacuum gripping of the can body at any time throughout the cycling when there should be vacuum gripping by the vacuum supply being open, the resulting unusual continuous vacuum flow will be sensed by the vacuum flow sensor 72 and the pusher mechanism 62 and/or the entire trimmer shut down. Thus, this provides a further safety feature preventing component damage or improper operation.

TRIMMING MECHANISM ASSEMBLY The trimming mechanism assembly 34 is shown in general trimmer location in FIGS. 1 and 2, and is best seen in detail in FIGS. 8 through 15. Generally, the prime components of the trimming mechanism assembly 34 or those components which actually perform the metal trimming of an untrimmed can body 44 are an outer annular anvil or cutter ring 104 having a radially extending cutting surface 106 and an internal trimmer knife 108 having a radially extending cutting surface 110, these components in can body trimming position being shown in FIGS. 10, I2 and 14. Furthermore, important to certain of the principles of the present invention, the cutter ring 104 is stationary, as is the untrimmed can body 44 during the trimming operation, while the trimmer knife 108 is rotatable about its central knife axis, the knife and its axis are rotatable about a central axis of the trimming mandrel 66 and the untrimmed can body 44 being trimmed, and is radially movable outwardly to the trimming position shown as well as movable radially inwardly of the walls of the untrimmed can body, all of which is accomplished by structure to be described immediately below.

In addition to the components hereinbefore pointed out, the trimming mechanism assembly 34 includes a main drive gear 112 rotatably driving a cutter and nipper frame 114 turning on the main frame 30 and rotatable about the central axis of the trimming mandrel 66. The cutter and nipper frame 114 terminates at the left as shown or at the trimming mandrel 66 first in an externally threaded scrap removal cylinder 116, a portion of which lies radially inwardly of the scrap disposal assembly 36, and finally in an end cap 118 which telescopes and journals a portion of the trimming mandrel 66 (FIGS. l0, l2 and 14). The trimmer knife 108 is secured to a knife shaft 120 in a manner to be hereinafter particularly described, with the knife shaft being freely journalled within a knife frame 122, which, in turn, is pivotally connected to the cutter and nipper frame 114 by securement to an axially pivotal control rod 124 pivotal on the cutter and nipper frame 114 (FIGS. 13, 14 and 15). As shown in FIGS. 14 and 15, the right end of the knife frame 122 is mounted on the right end of the control rod 124 and although the left end of the control rod is shown in FIG. 14 removed to expose other important parts of the mechanism, the left end of the knife frame 122 is similarly connected to the control rod.

Thus, the trimmer knife 108, knife shaft 120 and knife frame 122 are pivotally mounted on the cutter and nipper frame 114 for outward and inward and pivotal movement of the trimmer knife relative to the cutter and nipper frame about the axis of the control rod 124 which is widely offset from the central axis of the cutter and nipper frame. At the same time, the cutter and nipper frame 114 is rotatable about its central axis corresponding with the central axis of the trimming mandrel 66 being driven by the main drive gear 112 and carrying the trimmer knife 108 through the knife shaft 120 and knife frame 122 in this rotatable movement about the trimming mandrel central axis. In this manner, the trimmer knife 108 which is freely rotatable about its own central axis may be pivoted from its inner position inwardly of the stationary cutter ring 104 and an untrimmed can body 44 projecting through said cutter ring radially outwardly to cutting or trimming position extending radially through the untrimmed can body and against the cutter ring for rotation about the cutter ring to trim the entire circumferential length of the untrimmed can body. At the same time, the trimmer knife 108 may be retained inwardly in its retracted position free of the cutter ring 104 while still being constantly rotated about the central axis of the trimming mandrel 66 by the main drive gear 112 and the cutter and nipper frame 114.

The pivotal control of the trimmer knife 108 between its inward retracted and outward cutting or trimming positions is regulated by the mechanism shown in FIGS. 8, 13 and 14, such mechanism including a control arm 126 pivotal about the control rod 124 at one end and having a cam follower 120 rotatably mounted at the other end. The cam follower 128 bears outwardly against an internal cam surface 130 of a separately rotating cam ring 132, the cam ring being constantly rtatably driven by a cam gear 134 (FIGS. 8 and 14) at a different speed than the cutter and nipper frame 114 rotation, but about the central axis of the trimming mandrel 66. Intermediate the length of the control arm 126, an axially extending wedge 136 having an angled wedge surface 138 is received axially through an appropriate notch of the control arm and bears radially inwardly against the outer circumferential surface of the knife frame 122 so that the pivotal positioning of the trimmer knife 108, knife shaft 120 and knife frame 122 about the axis of the control rod 124 is determined by the control arm cam follower 128 and the cam ring internal cam surface 130. As shown in F1G. 13, the knife frame 122 is resiliently urged and maintained against and controlled by the wedge 136 through a radially movable plunger 140 mounted on the cutter and nipper frame 114 urged radially inwardly by a coiled spring 142.

Thus, the cam ring 132 controls the outward and inwardly pivoting of the trimmer knife 108 while this trimmer knife is being constantly rotated about the central axis of the trimming mandrel 66 through the cutter and nipper frame 114. With the particular form of internal cam surface 130 on the cam ring 132 and the particular form of trimmer of the present invention, the cam ring 132 constantly rotates two complete revolutions for every three complete revolutions of the constantly rotating cutter and nipper frame 114 about the central axis of the trimming mandrel 66 so that the trimmer knife 108 is pivoted outwardly into can body trimming position for one revolution of the cutter and nipper frame 114 and is pivoted inwardly free of any can body trimming action for two revolutions of the cutter and nipper frame. Therefore, three revolutions of the cutter and nipper frame 114 constitutes a cycle of the trimmer of the present invention.

As shown in FIGS. 14 and 15, the wedge 136 radially between the control am 126 and the knife shaft 120 is connected to the end of an axially extending cam positioning rod 144, the opposite end of said rod being threadably engaged in an adjustment dial 146 rotatable in the end of the knife frame 122. With such structure, rotation of the adjustment dial 146 in one direction will move the wedge 136 axially in one direction relative to the control arm 126, and rotation of the adjustment dial in the opposite direction will move the wedge axially opposite relative to the control arm. Since the wedge 136 contacts the control arm 126 through the angled wedge surface 138, this axial adjustment movement of the wedge will move the [knife shaft 120, knife frame 122 and trimmer knife 108 radially inwardly and outwardly relative to the central axis of the trimming mandrel 66. In this manner, therefore, the radial penetration of the trimmer knife 108 through the walls of the untrimmed can body 44 and relative to the outer stationary cutter ring 104 can be adjustably controlled.

It has been found that with the trimmer components as shown and described, penetration of the walls of the untrimmed can bodies 44 by the "trimmer knife 108 to one-half to three-quarters thickness of the walls will produce a satisfactory trimming operation. It is preferred, however, to penetrate the can body walls completely and approximately one-thousandth inch radially beyond by the trimmer knife 108 where the can walls have a metal thickness of approximately eightthousandths inch to insure a satisfactory can body trimming operation.

Referring to FIGS. 12 and 14, and more particularly to the unique mounting of the trimmer knife 108 on the knife shaft 120, it will be noted that the trimmer knife is annular and presents the radia1 cutting surface thereof axially against the cutting surface 106 of the cutter ring 104, that is, to the left .as shown in FIGS. 12 and 14. The end of the knife shaft is provided with a mounting cap 148 having a radially extending mounting surface 150 axially facing the trimmer knife cutting surface 110. In the assembly as shown, the trimmer knife 108 is selectively removably tightly secured to the mounting cap 148 with the trimmer knife cutting surface 110 tightly axially abutting the mounting cap mounting surface 150, and the mounting cap 148 is, in turn, selectively removably tightly secured abutting the end surface of the knife shaft 120.

Thus, since the knife shaft 120, although controllably movable radially inwardly and outwardly during the cycling for movement of the trimmer knife 108 between its inward retracted and outward trimming positions as hereinbefore described, always remains in a set axial positioning or always extends the same set axial distance or extent. With the mouting cap 148 in the assembly always tightly abutting the end surface of the knife shaft 120 and the trimmer knife cutting surface 110 in the assembly always abutting the mounting cap mounting surface 150, the important trimmer knife cutting surface 110 will always extend radially in the same axially located radial plane or at the same exact axial location. This means that with the described assembly, the trimmer knife cutting surface 110 will always be at the exact same axial location regardless of the axial thickness of the trimmer knife 108.

The importance of the foregoing relative to the mounting of the trimmer knife 108 is that during use of the trimmer, the cutting surface 110 of the trimmer knife 108 repeatedly requires surface grinding since this is the portion of the trimmer knife with the cutting surface 106 on the cutter ring 104 that is performing the can body wall metal trimming operation. When regrinding of the cutting surface 110 of the trimmer knife 108 is required, it is merely necessary to remove the mounting cap 148 from the knife shaft 120, remove the trimmer knife 108 from the mounting cap 148, regrind the trimmer knife cutting surface 110, and reassemble the various components as described, which, most importantly, will position the reground trimmer knife cutting surface 110 at the exact same axial location and regardless of the trimmer knife 108 now being slightly axially narrower. Using the trimmer knife cutting surface 110 as the mounting reference surface as described through axial abutment of this trimmer knife cutting surface against a mounting surface always axially located at the exact same axial location, such mounting surface being the mounting cap mounting surface 150, the trimmer knife 108 in its unique assembly with the mounting cap 148 is always quickly removable and replaceable after trimmer knife cutting surface 110 grinding without the danger of altering the alignment of the trimmer knife cutting surface with the required matching cutting surface 106 of the cutter ring 104. The removal and replacement of the trimmer knife 108can, therefore, be accomplished in a minimum of time, a far less time than has heretofore been possible with prior trimmer constructions.

A somewhat similar unique and advantageous mounting of the stationary cutter ring 104 on the main frame 30 is also provided according to the principles of the present invention as is best seen in FIGS. 10 and 12. As shown, the cutter ring 104 presents its radially extending and axial facing cutting surface 106 axially against the trimmer knife cutting surface 110 when the trimmer knife is in its outward can body wall trimming positioning. Thus, if the cutting surface 110 of the trimmer knife 108 is always in a set predetermined axial position, the facing cutting surface 106 of the cutter ring 104 must likewise always be at an exact predetermined axial positioning.

As shown, axially opposite the cutter ring cutting surface 106, the cutter ring 104 is secured axially abutting a generally L-shaped cross-section, mounting ring 152, a radially outwardly extending leg portion of the mounting ring radially outwardly of the cutter ring 104 also axially abutting a compensating spacer ring 154. The compensating spacer ring 154 is, except for its abutments, axially slideable relative to both the cutter ring 104 and mounting ring 152 extending axially radially adjacent portions of both. Intermediate the cutter ring 104, the compensating spacer ring 154 axially abuts a register ring 156 telescoping and radially outwardly abutting an axial portion of the cutter ring 104.

The register ring 156 by its inward radial abutment with the cutter ring 104 radially positions the cutter ring in exact location relative to the other components at the trimmer station 64, and is, in turn, radially outwardly recess registered with the main frame 30. At the same axial side of the register ring 156 with which it abuts the compensating spacer ring 154, the register ring axially abuts a register spacer ring 158 which, in turn, axially abuts the main frame 30, the register ring 156 and register spacer ring 158 being secured to the main frame 30. To complete the unique mounting assembly of the cutter ring 104, a clamping ring 160 is secured axially abutting the main frame 30 with a portion extending radially inwardly into axial alignment with a portion of the mounting ring 152, there being radially adjustable clamping studs 162 extending axially through the clamping ring 160 and adjustable tightly axially against the mounting ring 152.

With this described assembly and with the various components remaining with their exact same respective sizes, the cutter ring 104 will always be positioned in the exact same radial and axial location, and particularly, the cutting surface 106 of the cutter ring 104 will always be positioned in the same axial location or radial plane and relative to the cutting surface 110 of the trimmer knife 108 with which it must cooperate to accomplish the can body wall metal trimming operation. Obviously, the cutter ring 104 will always be retained in the same radial location by the register ring 156, but more important for purposes of the present invention, the cutter ring cutting surface 106 will always be retained in the same axial location and relative to the trimmer knife 108 by the cutter ring clamping to the mounting ring 152, the abutment of the mounting ring with the compensating spacer ring 154 and the abutment of the compensating spacer ring with the register ring 156 which is clamped in a predetermined axial position on the main frame 30. If nothing is altered, this exact axial positioning of the cutter ring cutting surface 106 will remain by the tight clamping of the clamping studs 162 of the clamping ring 160 against the mounting ring 152, but just as with the cutting surface 110 of the trimmer knife 108, the cutting surface 106 of the cutter ring 104 requires periodic grinding and if all of the other components of the assembly remain the same, the grinding of the cutter ring cutting surface 106 will move this cutting surface axially away relative to the trimmer knife cutting surface.

Thus, according to the principles of the present invention and with the unique assembly shown and described, when the cutter ring 104 is removed for grinding the radial cutting surface 106 thereof, the compensating spacer ring 154 is also removed and a radially extending surface thereof is ground an exact equivalent amount. For convenience, it is preferred to form the cutter ring 104 and the compensating spacer ring 154 with the exact same axial dimensions so that these two rings can be positioned with the compensating spacer ring 154 telescoping the cutter ring 104 on the same grinder and with the radially extending surfaces thereof radially aligned so that the grinding of the cutter ring cutting surface 106 will automatically grind the aligned radially extending surface of the compensating spacer 

1. In cutting mechanisms for metallic can body trimmers and the like of the type wherein a metallic can body is positioned on a mandrel with can body walls at a can body open end extending axially and a scrap ring as severed from the can body open end, the combination of: an outer cutter ring having an annular radially extending and axially facing cutting surface, an internal trimmer knife having a radially extending and axially facing cutting surface; reteNtion means operably associated with said can body for retaining said can body positioned on said mandrel during said severing of said scrap ring; cutter ring mounting means for mounting said cutter ring outwardly surrounding said can body walls at said can body open end with said can body walls extending axially through said cutter ring and said cutter ring cutting surface outwardly radially adjacent said can body walls during said can body retaining; trimmer knife mounting means for mounting said trimmer knife internally of said can body walls at said can body open end during said can body retaining with said trimmer knife movable generally radially outwardly from an inner retracted position to an outer trimming position at least partially penetrating said can body walls with said trimmer knife cutting surface axially adjacent said cutter ring cutting surface and then circumferentially around said can body walls with said trimmer knife cutting surface interacting with said cutter ring cutting surface to sever said scrap ring from said can body open end and then back generally radially inwardly to said retracted position; said cutter ring mounting means mounting said cutter ring with said cutter ring cutting surface in an exact predetermined axial position and including reference surface means associated with said cutter ring constructed and arranged to always remount said cutter ring cutting surface in the same said exact axial position despite dismounting of said cutter ring and axial reduction of said cutter ring cutting surface, said reference surface means including an annular surface extending radially parallel to said cutter ring cutting surface and determining said exact axial position of said cutter ring cutting surface when said cutter ring is mounted by said cutter ring mounting means, said annular surface of said reference surface means always being axially reduced the exact same axial reduction as said cutter ring cutting surface axial reduction during said dismounting of said cutter ring.
 2. Cutting mechanisms as defined in claim 1 in which said reference surface means includes a compensating spacer ring having oppositely axially facing and parallel radially extending surfaces, said compensating spacer ring radially extending surfaces being parallel to said cutter ring cutting surface, said compensating spacer ring axially determining said cutter ring cutting surface exact axial position during said cutter ring mounting by said cutter ring mounting means, said compensating spacer ring being axially reduced in exact same axial reduction as said cutter ring cutting surface axial reduction during said dismounting of said cutter ring.
 3. Cutting mechanisms as defined in claim 1 in which said reference surface means includes a compensating spacer ring having oppositely axially facing and parallel radially extending surfaces, said compensating spacer ring radially extending surfaces being parallel to said cutter ring cutting surface, said compensating spacer ring axially determining said cutter ring cutting surface exact axial position during said cutter ring mounting by said cutter ring mounting means, said compensating spacer ring always having an exact same axial thickness as said cutter ring at said cutter ring cutting surface.
 4. Cutting mechanisms as defined in claim 1 in which said reference surface means includes an annular surface extending radially parallel to said cutter ring cutting surface and determining said exact axial position of said cutter ring cutting surface when said cutter ring is mounted by said cutter ring mounting means, said annular surface of said reference surface means always being axially reduced the exact same axial reduction as said cutter ring cutting surface axial reduction during said dismounting of said cutter ring; and in which said trimmer knife mounting means mounts said trimmer knife with said trimmer knife cutting surface in an exact predetermined axial position and includes reference surface means associated with said trimmer knife constructed and arranged to always remount said trimmer knife cutting surface in the same said exact axial position despite dismounting of said trimmer knife and axial reduction of said trimmer knife cutting surface.
 5. Cutting mechanisms as defined in claim 1 in which said trimmer knife mounting means includes axially extending trimmer knife frame means having said trimmer knife mounted thereon, means mounting said trimmer knife frame means for movement of an axis thereof radially outwardly and inwardly carrying said trimmer knife between said inner retracted and outer trimming positions and for rotation of said trimmer knife frame means and trimmer knife circumferentially about a central axis of the can body being trimmed at least when said trimmer knife is in said outer trimming position; in which drive means is operably connected to said trimmer knife frame means for rotating said trimmer knife frame means and trimmer knife circumferentially about said central axis of the can body being trimmed at least when said trimmer knife is in said outer trimming position; and in which cam means is operably connected to said trimmer knife frame means for guiding said trimmer knife frame means and trimmer knife movement between said trimmer knife inner retracted and outer trimming positions and maintainment in said trimmer knife outer trimming position during said rotation circumferentially about said can body central axis including a cam ring circumferentially surrounding said trimmer knife frame means and having a radially inwardly facing cam surface, cam follower means radially outwardly engaged with said cam ring cam surface and operably connected radially inwardly of said cam ring to said trimmer knife frame means for guiding said trimmer knife frame means and trimmer knife movements during relative movement between said cam follower means and cam ring cam surface.
 6. In cutting mechanisms for metallic can body trimmers and the like of the type wherein a metallic can body is positioned on a mandrel with can body walls at a can body open end extending axially by an outer cutter means and an internal trimmer knife interacts against the cutter means to sever a scrap ring from the can body open end; the combination of: trimmer knife mounting means including axially extending trimmer knife frame means having said trimmer knife mounted thereon, means mounting said trimmer knife frame means for movement of an axis thereof radially outwardly and inwardly carrying said trimmer knife between inner retracted and outer trimming positions at least partially penetrating said can body walls and for rotation of said trimmer knife frame means and trimmer knife circumferentially about a central axis of said can body being trimmed at least when said trimmer knife is in said outer trimming position to interact with said cutter means severing said scrap ring; drive means for rotating said trimmer knife frame means and trimmer knife circumferentially about said central axis of the can body being trimmed at least when said trimmer knife is in said outer trimming position; cam means for guiding said trimmer knife frame means and trimmer knife movement between said trimmer knife inner retracted and outer trimming positions and maintainment in said trimmer knife outer trimming position during said rotation circumferentially about said can body central axis including a cam ring circumferentially surrounding said trimmer knife frame means and having a radially inwardly facing cam surface, cam follower means radially outwardly engaged with said cam ring cam surface and operably connected radially inwardly of said cam ring to said trimmer knife frame means for guiding said trimmer knife frame means and trimmer knife movements during relative movement between said cam follower means and cam ring cam surface.
 7. Cutting mechanisms as defined in claim 6 in which said drive means constantly rotates said trimmer knife frame means and trimmer knife circumferentially about said ceNtral axis of the can body being trimmed when said trimmer knife is in either of said inner retracted and outer trimming positions; and in which said cam means includes cam ring mounting means mounting said cam ring constantly rotatable circumferentially about and in a same rotational direction as said trimmer knife frame means and trimmer knife rotation but at a different rotational speed.
 8. Cutting mechanisms as defined in claim 6 in which trimmer knife adjustment means is operably connected to said trimmer knife for selectively adjusting maximum outward movement of said trimmer knife in movement into said outer trimming position determining penetration of said can body walls in said outer trimming position.
 9. Cutting mechanisms as defined in claim 6 in which trimmer knife adjustment means is operably connected to said trimmer knife through said trimmer knife frame means and said cam follower means of said cam means for selectively adjusting maximum outward movement of said trimmer knife in said outer trimming position of said trimmer knife determining penetration of said can body walls in said outer trimming position.
 10. Cutting mechanisms as defined in claim 6 in which trimmer knife adjustment means is operably connected to said trimmer knife for selectively adjusting maximum outward movement of said trimmer knife in movement into said outer trimming position determining penetration of said can body walls in said outer trimming position, said trimmer knife adjustment means including dial means operably connected thereto and selectively rotatable for selectively adjusting said maximum outward movement of said trimmer knife.
 11. Cutting mechanisms as defined in claim 6 in which said drive means includes a drive frame constantly rotatable about a central axis of a can body being trimmed; in which said means mounting said trimmer knife frame means for movement pivotally mounts said trimmer knife frame means and trimmer knife on said drive frame rotatable therewith; and in which said cam follower means in its radial outward engagement with said cam ring cam surface guides said trimmer knife frame means and trimmer knife pivoting on said drive frame.
 12. Cutting mechanisms as defined in claim 6 in which said drive means includes a drive frame constantly rotatable about a central axis of a can body being trimmed; in which said means mounting said trimmer knife frame means for movement pivotally mounts said trimmer knife frame means and trimmer knife on said drive frame rotatable therewith; in which said cam follower means in its radial outward engagement with said cam ring cam surface guides said trimmer knife frame means and trimmer knife pivoting on said drive frame; in which said cam follower means is pivotally connected to said trimmer knife frame means for limited pivotal movement relative thereto, the relative pivoted positioning of said cam follower means with respect to said trimmer knife frame means determining maximum outward movement of said trimmer knife in outer trimming position; and in which trimmer knife adjustment means is operably connected to said cam follower means selectively adjustable for determining pivotal positioning of said cam follower means with respect to said trimmer knife frame means.
 13. Cutting mechanisms as defined in claim 6 in which said drive means includes a drive frame constantly rotatable about a central axis of a can body being trimmed; in which said means mounting said trimmer knife frame means for movement pivotally mounts said trimmer knife frame means and trimmer knife on said drive frame rotatable therewith; in which said cam follower means in its radial outward engagement with said cam ring cam surface guides said trimmer knife frame means and trimmer knife pivoting on said drive frame; in which said drive means constantly rotates said trimmer knife frame means and trimmer knife circumferentially about said central axis of the can body being trimmed when said trimmer knife is in either of said inner retRacted and outer trimming positions; and in which said cam means includes cam ring mounting means mounting said cam ring constantly rotatable in a same rotational direction as said trimmer knife frame means and trimmer knife rotation but at a different rotational speed.
 14. Cutting mechanisms as defined in claim 6 in which said cam follower means is pivotally connected to said trimmer knife frame means for limited pivotal movement relative thereto, pivotal positioning of said cam follower means relative to said trimmer knife frame means determining maximum outward movement of said trimmer knife frame means and trimmer knife in said outer trimming position; and in which trimmer knife adjustment means is operably connected to said cam follower means selectively adjustable for determining pivotal positioning of said cam follower means relative to said trimmer knife frame means.
 15. Cutting mechanisms as defined in claim 6 in which said drive means constantly rotates said trimmer knife frame means and trimmer knife circumferentially about said central axis of the can body being trimmed when said trimmer knife is in either of said inner retracted and outer trimming positions; in which said cam means includes cam ring mounting means mounting said cam ring constantly rotatable in a same rotational direction as said trimmer knife frame means and trimmer knife rotation but at a different rotational speed; and in which trimmer knife adjustment means is operably associated with said trimmer knife for selectively adjusting maximum outward movement of said trimmer knife in movement into said outer trimming position determining penetration of said can body walls in said outer trimming position. 